The Sensex plunged as much as 1,294.4 points, or 1.7 per cent, to 76,120.5 amid a broad-based sell-off on Dalal Street while the Nifty50 gave up 335.8 points, or 1.4 per cent, to hit 23,183.6. All sectors were in the deep red, with financial, IT and energy shares leading the fall.